Freedom fighter PZ Meyers debated some theists recently. They tried to come at him with this idea that there is no empirical evidence for love, in an attempt to deflate his argument that belief in God is unjustified due to a lack of evidence.
He defended himself pretty well, pointing out that we witness empirical evidence of love every day. I just wanted to expand on his point.
We can imagine a world without love. We see examples of a loveless society in novels like Brave New World. It's a world significantly different from our own.
Now, close your eyes. Wait, open them. You'll need those to read this. But do whatever you need to do, aside from closing your eyes, that helps you imagine. Think about a world, or universe, without God. Think of the development of the universe and life on our planet as a combination of unlikely events, rather than the designed directive of a creative force.
How different is your world from the one in which we live?
In my mind, it's not different at all. That's the difference between needing evidence for love and evidence for God. The fact is that our world very much resembles a world without any interfering or creative God. Occam's Razor demands we avoid needlessly complicating the equation.